<!--
 * @Description: 
 * @Author: ljl
 * @Date: 2024-12-30 11:19:00
 * @LastEditors: rendc
 * @LastEditTime: 2025-05-30 16:54:21
-->
<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <ul>
    <li>1</li>
    <li>2</li>
    <li>3</li>
    <li>4</li>
    <li>5</li>
  </ul>
  <script>
    // const ul = document.querySelector('ul')  // ul
    // console.log(ul.children)  // 得到伪数组  选择的是 亲儿子 
    
    const li2 = document.querySelector('ul li:nth-child(2)')
    console.log(li2.previousElementSibling)  // 上一个兄弟
    console.log(li2.nextElementSibling)  // 下一个兄弟
  </script>
</body>

</html>